DUMBEST is a playable word

dumb Scrabble® Dictionary

adjective
dumber, dumbest
lacking intelligence
verb
dumbed, dumbing, dumbs
to make silent
99 Playable Words can be made from "DUMBEST"
   2-Letter Words (12 found)
   3-Letter Words (32 found)
   5-Letter Words (13 found)
   6-Letter Words (5 found)
   7-Letter Words (1 found)